On 14 April, the guided missile frigateUSS Samuel B. Roberts struck a mine while deployed in the Persian Gulf as part of Operation Earnest Will, the 1987–88 convoy missions in which U.S. warships escorted reflagged Kuwaiti oil tankers to protect them from Iranian attacks. The explosion blew a 4.5 m (15-foot) hole in the Samuel B. Roberts's hull and nearly sank it. The crew saved their ship with no loss of life, and the Samuel B. Roberts was towed to Dubai on 16 April. After the mining, U.S. Navy divers recovered other mines in the area. When the serial numbers were found to match those of mines seized along with the Iran Ajr the previous September, U.S. military officials planned a retaliatory operation against Iranian targets in the Persian Gulf.

According to Bradley Peniston, the attack by the U.S. helped pressure Iran to agree to a ceasefire with Iraq later that summer, ending the eight-year conflict between the Persian Gulf neighbors.[3]

On 6 November 2003, the International Court of Justice ruled that "the actions of the United States of America against Iranian oil platforms on 19 October 1987 (Operation Nimble Archer) and 18 April 1988 (Operation Praying Mantis) cannot be justified as measures necessary to protect the essential security interests of the United States of America." However, the International Court of Justice dismissed Iran's claim that the attack by United States Navy was a breach of the 1955 Treaty of Amity between the two countries as it only pertained to vessels, not platforms.[4]

On 18 April, the U.S. Navy attacked with several groups of surface warships, plus aircraft from the aircraft carrier USS Enterprise, and her cruiser escort, USS Truxtun. The action began with coordinated strikes by two surface groups.

One Surface Action Group, or SAG, consisting of the destroyers USS Merrill (including embarked LAMPSMK I Helicopter Detachment HSL-35 Det 1) and USS Lynde McCormick, plus the amphibious transport dockUSS Trenton and its embarked Marine Air-Ground Task Force (Contingency MAGTF 2-88 from Camp LeJeune, NC)[citation needed] and the LAMPS (Light Airborne MultiPurpose System) Helicopter Detachment (HSL-44 Det 5) from USS Samuel B. Roberts, was ordered to destroy the guns and other military facilities on the Sassan oil platform. At 8am, the SAG commander, who was also the commander of Destroyer Squadron 9, ordered the Merrill to radio a warning to the occupants of the platform, telling them to abandon it. The SAG waited 20 minutes, then opened fire. The oil platform fired back with twin-barrelled 23mm ZU-23 guns. The SAG's guns eventually disabled some of the ZU-23s, and platform occupants radioed a request for a cease-fire. The SAG complied. After a tug carrying more personnel had cleared the area, the ships resumed exchanging fire with the remaining ZU-23s, and ultimately disabled them. Cobra helicopters completed the destruction of enemy resistance. The Marines boarded the platform, and recovered a single wounded survivor (who was transported to Bahrain), some small arms, and intelligence. The Marines planted explosives, left the platform, and detonated them. The SAG was then ordered to proceed north to the Rakhsh oil platform to destroy it.

As the SAG departed the Sassan oil field, two Iranian F-4s made an attack run, but broke off when the Lynde McCormick locked its fire control radar on the aircraft. Halfway to the Rahksh oil platform, the attack was called off in an attempt to ease pressure on the Iranians and signal a desire for de-escalation.

Iran responded by dispatching Boghammar speedboats to attack various targets in the Persian Gulf, including the American-flagged supply ship Willie Tide, the Panamanian-flagged oil rig the Scan Bay and the British tanker York Marine. All of these vessels were damaged in different degrees. After the attacks, A-6E Intruder aircraft launched from CVN 65, USS Enterprise, were directed to the speedboats by an American frigate. The two VA-95, aircraft, piloted by "Lizards" Lieutenant Commander James Engler and Lieutenant Paul Webb, dropped Rockeyecluster bombs on the speedboats, sinking one and damaging several others, which then fled to the Iranian-controlled island of Abu Musa.[5]

Combat Patch of Operation Praying Mantis

Action continued to escalate. Joshan, an Iranian Combattante IIKaman-class fast attack craft, challenged the USS Wainwright and Surface Action Group Charlie. The commanding officer of Wainwright directed a final warning (of a series of warnings) stating that Joshan was to "stop your engines, abandon ship, I intend to sink you". The Joshan responded by firing a Harpoon missile at them.[6] The missile was successfully lured away by chaff.[7] The Simpson responded to the challenge by firing four Standard missiles, while Wainwright followed with one Standard missile.[8] All missiles hit and destroyed the Iranian ship's superstructure but did not immediately sink it, so the Bagley fired a Harpoon of its own. The missile did not find the target. SAG Charlie closed on the Joshan, with Simpson, then the Bagley and the Wainwright firing guns to sink the crippled Iranian ship.[6]

Two Iranian F-4 Phantom fighters were orbiting about 48 km away when Wainwright decided to drive them away. The Wainwright fired two Extended Range Standard missiles, one of which detonated near an F-4, blowing off part of its wing and peppering the fuselage with shrapnel. The F-4s withdrew, and the Iranian pilot landed his damaged airplane at Bandar Abbas.[8]

Fighting continued when the Iranian frigate Sahand departed Bandar Abbas and challenged elements of an American surface group. The frigate was spotted by two A-6Es from VA-95 while they were flying surface combat air patrol for the USS Joseph Strauss.

The Iranian frigate Sahand burning from bow to stern on 18 April 1988 after being attacked.

The Sahand fired missiles at the A-6Es, which replied with two Harpoon missiles and four laser-guided Skipper missiles. The Joseph Strauss fired a Harpoon. Most, if not all of the shots scored hits, causing heavy damage and fires. Fires blazing on the Sahand's decks eventually reached her munitions magazines, causing an explosion that sank her.

Late in the day, the Iranian frigate Sabalan departed from its berth and fired a surface-to-air missile at several A-6Es from VA-95. The A-6Es then dropped a Mark 82laser-guided bomb into the Sabalan's stack, crippling the ship and leaving it burning. The Iranian frigate, stern partially submerged, was taken in tow by an Iranian tug, and was repaired and eventually returned to service. VA-95's aircraft, as ordered, did not continue the attack. The A-6 pilot who crippled the Sabalan, LCDR James Engler, was awarded the Distinguished Flying Cross by AdmiralWilliam J. Crowe, Chairman of the Joint Chiefs of Staff, for the actions against the Sabalan and the Iranian gunboats.[9]

In retaliation for the attacks, Iran fired Silkworm missiles (suspected to be the HY-4 version) from land bases against SAG Delta in the Strait of Hormuz and against the USS Gary in the northern central Persian Gulf, but all missed due to the evasive maneuvers and use of decoys by the ships. A missile was probably shot down by the Gary's 76 mm (3.0 in) gun. The Pentagon and the Reagan Administration later denied that any Silkworm missile attacks took place probably since it was the only way to keep the situation from escalating further as they had promised before publicly that any such attacks would merit retaliation against targets on Iranian soil.[10]

Following the attack on the Sabalan, U.S. naval forces were ordered to assume a de-escalatory posture, giving Iran a way out and avoiding further combat. Iran took the offer and combat ceased, though both sides remained on alert, and near-clashes occurred throughout the night and into the next day as the forces steamed within the Gulf. Two days after the battle, the Lynde McCormick was directed to escort a U.S. oiler out through the Strait of Hormuz, while a Scandinavian-flagged merchant remained near, probably for protection. While the ships remained alert, no hostile indications were received, and the clash was over.

By the end of the operation, American Marines, ships and aircraft had destroyed[2] Iranian naval and intelligence facilities on two inoperable oil platforms in the Persian Gulf, and sank at least three armed Iranian speedboats, one Iranian frigate and one fast attack gunboat. One other Iranian frigate was damaged in the battle.[11]Sabalan was repaired in 1989 and has since been upgraded, and is still in service with the Iranian navy. The fires eventually burned themselves out but the damage to the infrastructure forced the demolition of the Sirri platforms after the war.[citation needed] The site was built up again for oil production by French and Russian oil companies, after buying the drilling rights from the Iranian government.[citation needed]

The U.S. side suffered two casualties, the crew of a Marine Corps AH-1T Sea Cobra helicopter gunship. The Cobra, attached to the USS Trenton, was flying reconnaissance from the Wainwright and crashed sometime after dark about 15 miles southwest of Abu Musa island. The bodies of Capt. Stephen C. Leslie, 30, of New Bern, N.C., and Capt. Kenneth W. Hill, 33, of Thomasville, N.C., were recovered by Navy divers in May, and the wreckage of the helicopter was raised later that month. Navy officials said it showed no sign of battle damage.[12]

A month later, the guided missile cruiser USS Vincennes arrived, summoned in haste to protect the frigate Samuel B. Roberts as it was hauled back to the United States. On 3 July, the Vincennes shot down Iran Air Flight 655, killing all 290 crew and passengers. The U.S. government said the crew of the Vincennes mistook the Iranian Airbus for an attacking F-14 fighter, despite it being a commercial airliner flying a scheduled route. The Iranian government alleged that the Vincennes knowingly shot down a civilian aircraft.

On 6 November 2003 the International Court of Justice dismissed a claim by Iran and a counter claim by the United States'[4] for reparations for breach of a 1955 'Treaty of Amity' between the two countries. In short the court rejected both claim and counter claim because the 1955 treaty protected only "freedom of trade and navigation between the territories of the parties"[4] and because to the US trade embargo on Iran at the time, no direct trade or navigation between the two was affected by the conflict.

The court did state that "the actions of the United States of America against Iranian oil platforms on 19 October 1987 (Operation Nimble Archer) and 18 April 1988 (Operation Praying Mantis) cannot be justified as measures necessary to protect the essential security interests of the United States of America." The Court ruled that it "...cannot however uphold the submission of the Islamic Republic of Iran that those actions constitute a breach of the obligations of the United States of America under Article X, paragraph 1, of that Treaty, regarding freedom of commerce between the territories of the parties, and that, accordingly, the claim of the Islamic Republic of Iran for reparation also cannot be upheld;".[4]

^"Will Block Oil Traffic if Its Tankers Are Stopped: Iran;" Los Angeles Times Los Angeles, Calif.: 18 May 1988. pg. 7. In his recent book "Tanker War", author Lee Allen Zatarain indicates there was some indication they may have crashed while evading hostile fire from the island.